This invention relates generally to an appliance, and more particularly, to a built in wall oven.
A wall oven may be one or more oven units separated from a cook top surface or stove unit. It may also include a microwave or speed-cooking appliance. The built in oven is often in a cavity surrounded by a cabinet or has wall surfaces in close proximity to the oven external surfaces. Further, there is generally poor airflow and often an inability to remove heated air from above and around the built in wall oven.
Generally, the wall oven utilizes an electric or gas heating element. Some wall ovens known as a self-cleaning wall oven have a self-clean cycle. During the self-clean cycle the interior temperatures of the oven may reach more then 425° C. Thus the exterior surfaces can become very hot which in turn can cause wood or other construction materials surrounding the built in wall oven to become heated, potentially to the point of combustion. It has therefore become the industry practice to include a forced air ventilation system around the wall oven to exhaust the heated air in the cavity.
Various forced air-ventilating systems for self-cleaning wall ovens have been developed. Particularly, ventilating systems for self-cleaning ovens in which a forced air fan is not provided have been developed. In such an arrangement the passages around the oven are arranged to obtain sufficient air movement by convection. Obviously when the inner walls of the oven reach high temperature levels, the heat tends to radiate or be convected or conducted to outer walls, thereby raising the outer walls to undesirably high and possibly unsafe temperature levels. Attempts have been made to overcome this problem by supplying additional baffling to prevent some of the internally generated heat from contacting the outer wall structure. This reduces the volume of the cooking cavity of the oven and reduces consumer satisfaction.
With increasingly stringent surface temperature limits being imposed upon range and installed oven manufacturers, in some installations it is questionable whether the convection ventilating systems will meet the requirements. As to those arrangements which include forced air fans, the airflow paths are not considered to be optimized to obtain the most advantageous results, and in some of the arrangements dampers are provided, which while inexpensive, in some instances will block convection flow if a failure of the exhaust fan occurs.
Recently the market has seen a proliferation of programmable cooking controls or computerized cooking controls in appliances. These controls may include LCD screens, microswitches and touchpanel displays. These devices contain semi-conductor chips, integrated circuits, photodiode displays and the like, which are designed to operate within a limited range of environmental temperature, and may become destroyed, degraded or inoperative if subjected to too high a temperature for too long a length of time. Often, such electronic controls are not manufactured by the manufacturer of the oven but purchased as a standard item from an outside supplier. These standard or “off the shelf” components often have a temperature limit of approximately 105° C.
To reduce the temperature that these components are subjected to, oven manufactures have traditionally used down draft or reverse flow cooling. In these types of cooling flow patterns, air is drawn into the oven at the controls. This causes the air around the controls to be at or near the ambient temperature of the room. However, to complete the cooling of the oven, the air drawn in at the controls is then forced by a fan down along the sides of the oven and out the base. This causes the fan to be of larger capacity than necessary as it must counter the natural tendency for the hot air in the oven baffles to rise.